Sugar mills in southern Louisiana and in Florida generate large amounts of bagasse, which is a fibrous, pithy by-product of the sugar cane processing. A major part of the U.S. production of cane sugar is from the sugar mills in the Mississippi river delta and Bayou Teche regions of Southern Louisiana. The principal cane harvest there is from about October through January, and the quantity of bagasse by-product builds up to the point where it represents a major disposal problem.
In the past, this bagasse has been burned as an additional source of energy for the sugar refining process. However, almost all the sugar mills have switched over to natural gas because it is dependable, easy to control, and significantly reduces air pollution. With the complete changeover to natural gas heat sources, the surplus bagasse by-product has created a disposal problem of substantial proportions at the sugar mills.
Storage the bagasse, or using it for landfill are not satisfactory answers to the problem, because the delta country is low and flat, and valuable for additional sugar cane production. The prices obtained for sugar have increased steadily with demand, especially since purchases from Cuba have been effectively cut off, so all available sugar producing land is needed.
During the past twenty-five years, many different proposals for using the surplus bagasse have been explored. It has been used in various animal feed combinations, and numerous studies have been made to evaluate the weight gain value in livestock fed large quantities of bagasse (which is primarily ligno-cellulose pith and fibers). Findings were generally inconclusive. Other forage materials were as good or better in most livestock diets, and in some tests, the bagasse-containing diets were not as desirable as conventional forage materials, even for maintenance diets.
Many attempts have been made to up-grade the nutritional value of bagasse, and varying degrees of success have been reported, but when attempts were made to combine bagasse with molasses (also a by-product of the sugar milling industry) the handling of the resulting hygroscopic mixture was an immediately evident problem.
The bulky nature of the bagasse had always been a deterrent to extensive use in animal feeds, and its low utilization value as a nutrient was a further obstacle to serious efforts to use it. Other feed carriers, such as bran and soybean hulls were at first reasonably priced, so little was done to tackle the problem, and to reduce the ever-building bagasse surplus.
Always hovering close at hand was the thought bagasse might be upgraded by recombining it with blackstrap molasses, another sugar mill by-product. Such a blending at or near the sugar mill would incur no shipping costs, and little handling cost for either raw material component, so numerous intermittent attempts have been made to develop bagasse/molasses animal feed combinations. The rationale behind these efforts was well based, because the high nutrient value of blackstrap molasses in livestock feeding programs was already well known, but even dehydrated molasses is hygroscopic, and tends to lump and clump to a sticky, unmanageable mass after exposure to humid air for even a short time.
When soybean hulls, or other millfeed carriers, such as bran or corn wet milling by-products were used as a molasses feed carrier, it made most sense to ship the dense molasses in tank cars to the location of the more bulky carrier, and do the blending steps at the location, usually a region of temperate climate, average or low relative humidity, and generally cooler temperatures than are experienced the greater part of the year in Southern Louisiana, and in most sugar cane growing areas of the world. Such regions include those areas in latitudes up to approximately 30.degree. north or south of the equator in locations where topography, rainfall and temperature combine to give the tropical, humid climate required for good sugar cane production. Sugar cane regions include: Southern Louisiana and Florida, and also Hawaii, many Caribbean Islands, Central and Northern South America, parts of Mexico, Spain, China, Australia, Indonesia, Philippines, India, Pakistan and the Replubic of South Africa.
The relative humidity in the Mississippi delta country where most U.S. sugar mills are located is rarely below 50%. The climate is considered "tropical", with frequent heavy rainfall. The delta is adjacent to North America's principal source of rain and snow, and a good part of that rain falls back onto the sugar cane country throughout the year without ever leaving the Gulf of Mexico. Any can molasses derived material, therefore, has an unusually good opportunity to exhibit its moisture loving characteristics in the locale of its origin. In spite of the handling difficulties, attempts have continued to combine molasses and bagasse.
The prices of other molasses carriers, such as soybean hulls, have increased drastically over the past 25 years, with major increases in the last 2 years. As recently as 1950, soybean hulls sold for about $10.00/ton; the 1971 price was about $43.00/ton; and, in 1973, a price for this same animal feed carrier was about $80.00/ton. This phenomenal increase is believed due largely to the great success soybean hulls have enjoyed as a nutritional carrier for animal feeds, but they are getting "out of sight". By comparison, in 1971 bagasse sold for about $3.96/ton, less than one tenth the cost of soybean hulls. It can be seen there was a substantial economic incentive to find successful ways to utilize the ever increasing supply of bagasse. The State of Louisiana has invested substantial sums to explore possible uses for this material. A substantial study has been made in Pakistan to determine nutritional value in livestock feed. A major South African sugar milling company has formed a special company to utilize bagasse in animal feeds, and apparently has an interest in a second company which will design and build bagasse/molasses animal feed factories adjacent to sugar mills. In Puerto Rico, a major U.S. oil company invested in a fibre board factory which utilizes bagasse as the major raw material. A sugar mill near Tampa, Florida set up a facility for making animal feeds from bagasse/molasses combinations. All of these ventures have been faced with substantial obstacles inherent with bagasse and molasses handling, and climate (humidity) has contributed, too. The various ventures have enjoyed only a modicum of success, and many have "hung it up". The most promising possibility for using bagasse under present world economic conditions appears to be in the field of animal feeds.
The advantages of locating the sugar cane country are obvious cost savers in handling and shipping both the molasses and the bagasse. The bagasse, as it comes from the mill, is fluffy and difficult to handle. The molasses is normally placed in tanks for shipping, and requires a fairly high level of special technique to be handled efficiently. There are special storage problems, and in some instances molasses stored in Hawaii has been known to self-ignite and explode in storage, and thereafter burn, destroying a substantial portion of the valuable commodity. Other similar self-ignition storage losses have been reported in the Caribbean and at Puerto Rico.
Another good reason for avoiding shipment of molasses long distances is the fact that it normally contains about 20-30% by weight water. If it is possible to remove the water, while retaining the valuable nutrients of the molasses in the resulting animal feed, a substantial shipping cost can be avoided.